Method of ascertaining unknown data



July 20, 1954 E. w. SPRINGER METHOD OF ASCERTAINING UNKNOWN DATA 3Sheets-Sheet 1 Filed Jan. 2, 1946 TEMPERATURE FIG. I

FIG. 2

PERISCOPE DEPTH RANGE Hm IEmo grwmto'z EARL W. SPRINGER TEMPERATURE(60F. PER IN.)

TEMPERATURE FIG. 3

PERISCOPE 0 H R E: 3000 YD.

H: I50 FT.

ASSURED RANGE: I500 YD.

PATTERN: MIKE FIG. 6

FIG. 5

y 9 1954 E. w. SPRINGER 3, 7

METHOD OF ASCERTAINING UNKNOWN DATA Filed Jan, 2, 1946 3 Sheets-Sheet 2PERISCOPE p DEPTH RANGE: 400G YD.

LAYER DEPTH: 59 FT.

ASSURED RANGE: 90K) YD.

ASSURED RANGE DEPTH FT.

PATTERN 2 PETER 28 450 TEMPERATURE (60F. PER In.) FIG 8 H6. 7

awe/whom EARL W. SPRINGER July 20, 1954 E. w. SPRINGER METHOD OFASCERTAINING UNKNOWN DATA 3 Sheets-Sheet 3 Filed Jan. 2, 1946 FIG, l2

gwumn/ocm EARL WV SPWNGER Patented July 20, 1954 METHOD OF ASCERTAININGUNKNOWN DATA Earl W. Springer, Indianapolis, Ind. Application January 2,1946, Serial No. 638,694

1 Claim. (01. 73-339) (Granted under Title 35, U. S. Code (1952),

sec. 266) This invention relates to optical projection means for thecomparison of observed data with standard data. More particularly thisinvention relates to a means for comparing an observed trace oftemperature versus depth with standard 5 covery are interpreted by theuse of charts, traces of known characteristics. tables, special sliderules and the like. Such Successful use of underwater sound detectioninterpretation is subject to a number of disadequipment depends upon thepower output of the vantages, particularly, where the results of theprojector equipment in the direction of the tarin interp n m be q i yand accurately get, the amount of sound reflected by the targetdetermined which is necessary in naval practice. to the receivingequipment, and upon the spread- Existing means of interpretation areslow since ing and weakening of the soundbearn as it travels they arecomprised of a number of steps. In from projector to the target and backagain. If addition they are necessarily approximate, leadthecharacteristics of the underwater sound in to r ul f a l w r r faccuracy. p r equipment and the reflection characteristics of ainterpretation in addition depends po the target are known it remains topredict the training and experience that the operator or the spreadingand weakening of the sound beam reader has acquired. Anotherdisadvantage reunder various thermal conditions. sides in the fact thatonly one operator under If the temperature of the water did not varynormal circumstances makes the interpretation with depth, the sound rayswould travel in and results are therefore subject to misinterprestraightlines since the velocity of sound would be tation by s pe roughly thesame at all depths. Under such cont S n Obj t o y invention t provideditions a given detection range could be realized means for rapidinterpretation of bathytherregardless of the depth of the target.UnformOgraph tracestunately, however, the velocity of sound is not An thO je t o y invention iS t provide the same at all depths. The velocityof sound in means which will enable the interpretation of a sea waterincreases from 4700 feet per second to temperature-depth trace moreaccurately and 5300 feet per second when the temperature inwith lesschance for error than previous methods creases from degrees F. to 85degrees F. of interpretation.

Because of temperature gradients, sound rays so It is a further objectof my invention to enable do not travel in straight lines but followcurved n interpre ti n of t mp tu pth data by paths and are bent, orrefracted, away from levels untrained n in xp i p r nn lof hightemperature and high sound velocity It is still another object of yinvention to toward levels or low temperature and low sound pr vid a vif r int p in traces by omvelocity. Where the temperature decreases with7 5 p s With Standard traces, Which device is depth the sound rays arecurved downwardly, sufliciently light and small as to enable mountandthe targets near the surface may be detected ing on Ila-Val Vesselsonlyat close range. Where the temperature of It is y t another Object of yinvention to p the water increases with depth, which sometimes vi e mens f r pre traces which is o u s W e e a Warm body of Water during thean adaptable to electrocardiograph traces or other mixing process formsa layer over a colder body, traces o OW Characteristicsthe sound raysare bent upwardly towards the In t e d w s surface and targets locatedbelow the layer Figure 1 shows a temperature-depth trace dept are hiddenexcept at short range. under conditions of constant temperature;

In order to predict the capabilities of under Figure 2 shows thedirection of propagation of W ter ound 01' echo equipment under a giventhe sound rays under the constant temperature set of thermal conditions,it is necessary to know conditions; the variation of temperature withdepth in the Figure 3 shows a temperature-depth trace area in which theoperation is taking place. under conditions of negative temperature gra-Range information obtained from the temperadient; ture-depthcharacteristics determines the condi- Figure 4 illustrates the bendingof the sound tion under which sound equipment must advisedrays under theconditions corresponding to thely be used, for example, the spacing ofthe vessels trace of Figure 3; forming an under water search screen.Figure 5 shows a frame or slide of a standard In order to obtain thetemperature-depth 2 characteristics a device known as thebathythermograph is lowered into the water producing a temperature-depthtrace on a piece of smoked glass or similar backing. Such traces afterrecurve or trace and the associated data;

Figure 9 shows the projection analyzing means corresponding to oneembodiment of my invention;

Figure 10 illustrates the image cast upon the screen by the analyzingequipment;

Figure 11 shows one way' in which my inven'- tion may be practiced bythe use of a single projection;

Figure 12 illustrates another embodiment of myinvention in which atranslucent screen is used,

enabling two projectors to be placed on opposite sidesof the screen;

Figure 13 disclose still another embodiment in which a standard trace isprojected upon the slide containing the observed trace.

Figure 2 illustrates t the range is practically independent oi depthwhere the temperature of thewater is the same at all points. Figure 4shows the downward bending of the sound rays under negative temperaturegradient conditions. The conditions corresponding to Figures 2 and 4rarely exist and traces shown in Figures 1 and 3 are normally notobtained by bathythermograph equipment. The traces'shown in Figures 5and '3', however, are typical of the temperature-depth traces obtainedin practice. In the Figures 6 and 8 the region to the right of the heavyline 2'9 cannot be reached by the underwater detection gear, andsubmarines located at positions 22 and Ed are eifectively out of therange of the detection apparatus.

The traces 2i: and 28 shown in Figures 5 and 7 respectively are but twoof several hundred possible observed traces corresponding to a wide varity of underwater thermal conditions. The wide variety of the conditionsencountered makes it advisable that the burden of interpretation beremoved from the operator or reader of the observed trace. I thereforepropose that a large number or" standard traces be prepared beforehand,ror example on slides or frames 39. Because of the large number oftraces required to cover the possible existing thermal conditions, Iprefer to include the data of slides 30 on consecutive frames of moviefilm suitable for use in a microfilm projector. The curves arepreferably included on the film in proper order or ro- I tation so thatthe variation from one curve to the curve existing on adjacent frameso'ccursin' small increments.

My invention will be more completely understood by a description of theembodiment illustrated in Figure 9. In this figure the numeral 32represents a projector suitable to receive a slide 3!; bearing anobserved trace of temperature versus depth. The image 36 of the trace isthrown upon a screen or receiving surface 38. An additional projector itequipped with a roll of film 42 of standard traces and accompanying dataprojects a trace 44 on the screen 38. Simultaneously the datacorresponding to the curve 44 is cast upon the screen in the area 56. Inoperation the observed trace 35 is first cast on the screen and a sampletrace 44 cast on the screen in adjacent or superimposed relation forpurposes of comparison. The frames may be advanced one by one, forexample by means of crank 48, until a curve is found which issubstantially congruent with the observed trace. The observed trace datamay then be immediately read from the area 46. The matching may requirethat the two curves be movable with respect to one another. To enablesuch adjustment, adjusting means controlling angular rotation of eitherof the pro jectors may be used. For purposes of comparing the observedtrace with a standard trace, it is not necessary that the size of eitherimage must be adjusted for each comparison; since the relative size ofthe curves or traces 36 and 44 may be initially adjusted, however, byaxial movementof one-or both of the projectors.

In the embodiment of my device shown in Figure 11 the same opticalsystem is used for projecting both the observed trace and the sampletrace on the screen. While this method requires only one projector,which is advantageous on shipboard, nevertheless, it is not quite asflexible as the arrangement shown in Figure. 9. It will be necessary touse a film having standard traces of the same size as the observedtraces if both the observed and standard traces are placed in the samefocal plane.

In Figure 12 I have shown an arrangement in which the observed trace andthe standard trace and, its associated data are projected onto atranslucent screen from the opposite sides. This arrangement enables theprojector 4% associated with the film containing the standard traces tobe mounted in a housing 54. If desired the size of such housing may bereduced, for example by mounting the projector 4% in the region 56 andproviding appropriate reflecting means interposed between the projectorcc and the screen 38.

In order to facilitate the shifting from one frame to the frameadjacent, a driving means 58 may be provided to drive the filmcontaining the sample traces. Such means may, for example, consist of anelectric motor arranged to advance the film rrame-by-frame in rapidsuccession under the control of a reversing type pushbutton E8 in amanner well known in the control or motors. In my prefererd embodimentthe pushbutton control is of such a nature that the'speed of the drivingmeans is under the control of. the operator. This control may beaccomplished by variable resistance inserted in the motor circuit, bythe adjustment of a mechanical governoror the like. If desired the speedcontrol resistance may be inserted inthe same housing in which thepushbutton is contained.

In Figure l-3 is shown an embodiment in which the slide 34- containing'the observed trace 36 serves in itseli as ascreen to receive theprojection of the standard trace 44. The projector 32 may beof the sametype shown in Figures 9 and 11 already discussed. The portion 46 of theprojected frame is received on an auxiliary translucent. screen 59placed adjacent the slide 34-. In order that the projected trace bevisible through the smoked or semi-opaqued surface of the slide, it isnecessary that the prepared surface of the slide 3 be sufficientlytranslucent to permit the standard trace 44 to-be seen;

Ithas been found that observed temperature depth traces are readilyclassified into five pattern types. The. standard traces. falling undereach. of these types are preferably grouped in the same portion of the.film. Thus it is possible for the operator to note into which patterncategory the trace falls and to speed up the driving means 58 until theappropriate region of the film is reached. The process of comparison maythen proceed on a; frame-by-frame basis at a slower rate until a propermatch has been obtained. The accuracy of such match may then beinstantly checked by observation by the responsible individual in chargeof the reading.

In a practical application data corresponding to the trace may includethe periscope depth range, the layer depth, the assured range and thepattern classification as illustrated in Figures 5 and 7. Normally thisdata is immediately transmitted by radio or other means to other shipscontaining underwater sound equipment which are not, however, equippedwith bathythermograph apparatus. Because of the dependence of otherships upon the ship containing the traceanalyzing apparatus, it isparticularly necessary that such readings be obtained quickly andaccurately.

In view of the above it will be seen that my method of analysis isparticularly well adapted to underwater sound problems. I wish to pointout however, that this method of analysis is also well adapted to thereading of traces obtained on medical diagnostic equipment, for example,an electrocardiograph. At the present it is necessary forelectrocardiograph traces to be analyzed by a person having broadknowledge and experience of heart disease and associated disorders. Itwill be obvious that the specialist may leave the interpretation of suchreadings to his untrained medical assistant if projection analyzingapparatus and standard traces corresponding to various heart conditionsare used in a manner completely analogous to that just discussed.

It will be seen from the above that I have produced a method of andapparatus for quickly and accurately analyzing data which formerlyrequired the exacting attention of an operator with much training andexperience. It will further be seen that the arrangement which I havedisclosed utilizes apparatus which is inexpensive to construct and easyto maintain. Since film such as microfilm when used in a properly builtprojector is practically indestructible, it will be obvious thatreplacement of the film will rarely be necessary. Because of thewellknown splicing techniques additions may be easily made at any pointin the series of standard traces.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawings and havedescribed herein only the preferred embodiments. It is to be understood,however, that I do not aim to limit the invention by such disclosures,for I aim to cover all modifications and alternative constructionsfalling within the spirit and scope of the invention as defined in theappended claim.

The invention described herein may be used by or for the Government ofthe United States for governmental purposes without the payments of anyroyalties thereon or therefor.

What is claimed is:

A method for determining the effective range of sound transmissionthrough water by underwater sound apparatus comprising the steps ofobtaining a temperature-depth trace by submerging a bathythermographinto the water region through which the sound transmission is to bepropagated, projecting upon a screen the obtained temperature-depthtrace, projecting upon said screen a series of standardtemperature-depth charts of predetermined sound range characteristicshaving incremental differences in characteristics between successivetraces depict ing possible underwater thermal conditions in successionand in superimposed relation upon the projected image of the obtainedtemperaturedepth trace, comparing the projected image of the obtainedtemperature-depth trace and the projected images of said standardtemperaturedepth traces, and selecting a standard temperature-depthtrace having a shape substantially identical to the obtainedtemperature-depth trace, whereby the predetermined sound rangecharacteristics associated with the selected standard temperature traceare applicable to the water region through which sound is to bepropagated.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 595,541 Hollen Dec. 14, 1897 1,285,857 Welch Nov. 26, 19181,394,797 Smith Oct. 25, 1921 1,421,042 Twyman June 27, 1922 1,424,556Cooke Aug. 1, 1922 1,703,933 Hartness et al. Mar. 5, 1929 1,789,009 LuceJan. 13, 1931 2,035,780 Beardsley et al Mar. 31, 1936 2,155,248 Adams eta1. Apr. 18, 1939 2,192,529 Thomas et a1 Mar. 5, 1940

